[Ipopt] Empty solution in funcs.iterfunc using Matlab wrapper

[Xinhua Zhang]

Hi All,

I am using the Matlab mex of IPOPT for 64-bit Windows, which was downloaded
directly from the web site.  In the funcs.iterfunc callback, the x field of
the third argument (which is supposed to be the current solution), becomes
an empty matrix after two iterations (ie after funcs.iterfunc has been
successfully called for two times):

ans = 

                      x: []
                 inf_pr: 11.3335
                 inf_du: 999.0005
                     mu: 11.3335
                 d_norm: 0
    regularization_size: 0
               alpha_du: 0
               alpha_pr: 2.2737e-13
              ls_trials: 40

x was not empty in the first two iterations.  Does anyone know the cause
and/or a solution?

Thanks a lot.

Xinhua